NANOSYNTHESIS OF TERFENOL-D ENABLED BY HIGH ENERGY BALL MILLING

Magnetostrictive materials deform in response to a magnetic field or exhibit magnetization variation when mechanically stressed. This unique energy coupling between magnetic and mechanical domains is instantaneous and has resulted in a variety of acoustic sensors that can generate or detect surface acoustic waves, shear waves, or longitudinal waves. Despite their great potential, applications of magnetostrictive acoustic sensors are currently limited due to the difficulties in manufacturing and sensor integration. Additive manufacturing of magnetostrictive materials could simplify sensor installation, slash waste production, and reduce fabrication cost. This study used a commercial high energy ball mill to synthesize magnetostrictive nanoparticles that are crucial feedstock for fused filament fabrication, direct ink writing, or other additive manufacturing techniques. The effect of ball milling settings, such as milling duration, on particle size, purity, and morphology was studied. DLS confirmed a majority particle size distribution of around 155 nm for Terfenol-D powders dry-milled for 15 minutes. SEM images showed particles in the same nanoscale range, but had a majority of micro particles. Dry milling in argon also effectively prevented particle oxidation which are confirmed by EDS and XRD.